Allergic bronchopulmonary aspergillosis (ABPA), the most severe pulmonary complication caused by Aspergillus fumigatus (A. fumigatus), is considered to be a clinical syndrome with defined clinical, serological and pathological features. However, the diagnosis of ABPA is often difficult to make because a number of clinical and laboratory findings overlap with simple sensitisation to A, fumigatus. The shared characteristics between ABPA and A. fumigatus sensitisation include atopy, positive skin test, precipitins, elevated specific IgE and IgG to A. fumigatus extracts and elevated total lgE levels. To dissect the immune response to the fungus in different A. fumigatus-related complications we have cloned, characterised and produced a wide panel of IgE-binding molecules from this mould using a newly developed cloning system based on phage surface display of cDNAs. Phage, enriched from a surface display library using serum lgE of A. fumigatus-sensitised individuals or ABPA-patients, encoded two distinct classes of allergens: secreted or cytoplasmic proteins. Serologic analyses showed that the cytoplasmic proteins, among these manganese superoxide dismutase and acidic ribosomal P2 protein, are preferentially recognised by sera of patients suffering from ABPA. These disease-specific allergens allow a differential diagnosis of ABPA by serology or skin test with a specificity of 100% and a sensitivity >90%, demonstrating the potential of recombinant allergens for the precise diagnosis of allergic conditions.
Full conference title:
7th European Respiratory Society Annual Conference
- ERS 17th (2007)